Vehicle final drive unit (FDU) with wet clutch(es)

Abstract

A vehicle final drive unit (FDU) of a vehicle driveline. The vehicle FDU includes one or more wet clutches that provide disconnect capabilities in the vehicle FDU, and includes a final drive gearset. Different techniques are provided for discontinuing lubricant supply to the wet clutch(es) when the wet clutch(es) are disconnected in order to preclude unwanted rotations that can be the consequence of adhesion among clutch plates in the wet clutch(es). One technique actively brakes the final drive gearset in the vehicle FDU so that the final drive gearset no longer rotates and no longer throws lubricant to the wet clutch(es). Another technique involves closing an entrance that leads lubricant to the wet clutch(es).

What is claimed is: 
     
       1. A vehicle final drive unit (FDU), comprising:
 a final drive gearset driven by a driveline driveshaft; 
 a wet clutch activated to transmit rotation from said final drive gearset and to a driveline sideshaft, said wet clutch deactivated to cease transmission of rotation from said final drive gearset and to the driveline sideshaft, said wet clutch receiving thrown lubricant via rotation of said final drive gearset; 
 an actuator activating and deactivating said wet clutch, said actuator including at least one plate, said at least one plate moving to an actuated position in which said wet clutch is activated, and said at least one plate moving to a deactuated position in which said wet clutch is deactivated; and 
 a brake including a braking component; 
 wherein, upon deactivation of said wet clutch and movement of said at least one plate to the deactuated position, said at least one plate prompts engagement of said braking component with said final drive gearset and rotation of said final drive gearset is precluded and said wet clutch no longer receives thrown lubricant via said final drive gearset. 
 
     
     
       2. A vehicle final drive unit (FDU) of  claim 1 , wherein said final drive gearset includes a ring gear, the vehicle FDU further comprises a housing holding a lubricant bath, said ring gear is at least partly submerged in said lubricant bath and throws lubricant from said lubricant bath when said ring gear rotates, and at least some of the thrown lubricant is received by said wet clutch. 
     
     
       3. A vehicle final drive unit (FDU) of  claim 1 , wherein said braking component engages a differential housing when prompted by said at least one plate, and rotation of said final drive gearset is precluded via the engagement and said wet clutch no longer receives thrown lubricant via said final drive gearset. 
     
     
       4. A vehicle final drive unit (FDU) of  claim 1 , wherein said actuator includes a spring, said spring biasing said at least one plate to the deactuated position, said braking component is at least one disc, said at least one plate prompting engagement of said at least one disc with said final drive gearset. 
     
     
       5. A vehicle final drive unit (FDU) of  claim 4 , wherein said at least one disc includes a first disc and a second disc, said first disc is connected to said final drive gearset, said second disc is urged against said first disc by said at least one plate upon deactivation of said wet clutch and upon movement of said at least one plate to the deactuated position, the urging of said second disc against said first disc precludes rotation of said final drive gearset and discontinues throwing of lubricant to said wet clutch via said final drive gearset. 
     
     
       6. A vehicle final drive unit (FDU) of  claim 5 , wherein said first disc is connected to a housing of said final drive gearset and said second disc is carried by an extension of an intermediate housing in the vehicle FDU, said second disc moves on the extension toward and away from said first disc upon deactivation and activation of said wet clutch. 
     
     
       7. A vehicle final drive unit (FDU) of  claim 4 , wherein said at least one disc includes a first disc, a second disc, and a third disc, and the vehicle FDU further comprises a wall located at least partly in an interior of the vehicle FDU, said first disc is connected to said final drive gearset, said second disc and said third disc are carried by said wall via a slot-spline interrelation, and, upon deactivation of said wet clutch and upon movement of said at least one plate to the deactuated position, said at least one plate urges said first, second, and third discs together, and rotation of said final drive gearset is precluded and said wet clutch no longer receives thrown lubricant via said final drive gearset. 
     
     
       8. A vehicle driveline comprising said vehicle FDU of  claim 1 , and comprising a vehicle power transfer unit (PTU) located upstream of said vehicle FDU relative to transmission of torque in the vehicle driveline, said vehicle PTU lacking a brake that precludes rotation of components in said vehicle PTU. 
     
     
       9. A vehicle final drive unit (FDU) of  claim 1 , wherein said braking component is a pin, and wherein, upon deactivation of said wet clutch and movement of said at least one plate to the deactuated position, said at least one plate prompts engagement of said pin with said final drive gearset and rotation of said final drive gearset is precluded and said wet clutch no longer receives thrown lubricant via said final drive gearset. 
     
     
       10. A vehicle final drive unit (FDU) of  claim 1 , wherein said braking component is a clutch pack, and wherein, upon deactivation of said wet clutch and movement of said at least one plate to the deactuated position, said at least one plate prompts engagement of said clutch pack with said final drive gearset whereby said clutch pack is activated and rotation of said final drive gearset is precluded and said wet clutch no longer receives thrown lubricant via said final drive gearset. 
     
     
       11. A vehicle final drive unit (FDU), comprising:
 a final drive gearset having a gear at least partly submerged in a lubricant bath of the vehicle FDU; 
 a wet clutch receiving lubricant thrown by rotation of said gear in said lubricant bath, said wet clutch activated to transmit rotation from said final drive gearset and to a driveline sideshaft, said wet clutch deactivated to cease transmission of rotation from said final drive gearset and to the driveline sideshaft; 
 an actuator activating and deactivating said wet clutch, said actuator moving axially relative to the driveline sideshaft between an actuated position in which said wet clutch is activated and a deactuated position in which said wet clutch is deactivated; and 
 an intermediate wall having an entrance leading lubricant to said wet clutch; 
 wherein, upon activation of said wet clutch, said actuator moves axially to the actuated position and opens said entrance for introducing lubricant to said wet clutch, and, upon deactivation of said wet clutch, said actuator moves axially to the deactuated position and closes said entrance to prevent lubricant from passing through said entrance. 
 
     
     
       12. A vehicle final drive unit (FDU) of  claim 11 , wherein said actuator includes a plate, said plate moving axially between the actuated and deactuated positions, and said entrance is closed in the deactuated position via surface-to-surface abutment between said plate and said intermediate wall. 
     
     
       13. A vehicle final drive unit (FDU) of  claim 11 , wherein said entrance is closed when said actuator is moved to the deactuated position via a surface-to-surface abutment between said actuator and said intermediate wall, said surface-to-surface abutment being generally situated in an axial direction with respect to the driveline sideshaft. 
     
     
       14. A vehicle final drive unit (FDU) of  claim 11 , wherein said entrance is closed when said actuator is moved to the deactuated position via a surface-to-surface abutment between said actuator and said intermediate wall, said surface-to-surface abutment being generally situated in a radial direction with respect to the driveline sideshaft. 
     
     
       15. A vehicle final drive unit (FDU) of  claim 11 , wherein a pocket is formed at least in part by said intermediate wall, said pocket fluidly communicating with said entrance, said pocket holding lubricant adjacent said entrance that is thrown by rotation of said gear in said lubricant bath. 
     
     
       16. A vehicle final drive unit (FDU), comprising:
 a housing holding a lubricant bath; 
 a final drive gearset located at least partly in said housing, a gear of said final drive gearset at least partly submerged in said lubricant bath; 
 a wet clutch receiving lubricant thrown by rotation of said gear in said lubricant bath, said wet clutch activated to transmit rotation from said final drive gearset and to a driveline sideshaft, said wet clutch deactivated to cease transmission of rotation from said final drive gearset and to the driveline sideshaft; 
 an actuator activating and deactivating said wet clutch; 
 an intermediate wall at least partly defining an entrance leading lubricant to said wet clutch; and 
 a brake; 
 wherein, upon activation of said wet clutch, said actuator moves to an actuated position and opens said entrance for introducing lubricant to said wet clutch, and, upon deactivation of said wet clutch, said actuator moves to a deactuated position and closes said entrance to prevent lubricant from passing through said entrance, and, upon deactivation of said wet clutch, said actuator prompts engagement of said brake and precludes rotation of said gear of said final drive gearset. 
 
     
     
       17. A vehicle final drive unit (FDU) of  claim 16 , wherein, upon deactivation of said wet clutch, said entrance is closed via surface-to-surface abutment between said actuator and said intermediate wall. 
     
     
       18. A vehicle final drive unit (FDU) of  claim 16 , wherein said brake includes at least one disc, and, upon deactivation of said wet clutch, said actuator prompts engagement of said at least one disc with said final drive gearset in order to preclude rotation of said gear of said final drive gearset. 
     
     
       19. A vehicle driveline comprising said vehicle FDU of  claim 16 , and comprising a vehicle power transfer unit (PTU) located upstream of said vehicle FDU relative to transmission of torque in the vehicle driveline, said vehicle PTU lacking a brake that precludes rotation of components in said vehicle PTU.